Definition and Overview

Pulmonary hypertension (PH) is a condition that is characterized by the presence of high blood pressure in the capillaries, veins, and arteries of the lungs. A patient suffering from this condition can experience frequent shortness of breath, dizziness, fainting spells, and even swollen legs. Pulmonary hypertension can lead to a more severe condition that can lead to possibly fatal conditions, like heart failure. There are five different types of pulmonary hypertension, as identified in the Dana Point 2008 Updated Clinical Classification System.

  • Pulmonary arterial hypertension or PAH
  • Pulmonary hypertension owing to left heart disease
  • Pulmonary hypertension owing to lung disease and/or hypoxia
  • Chronic thromboembolic pulmonary hypertension or CTEPH
  • Pulmonary hypertension with unclear multifactorial mechanisms

This condition was first identified in the late 1800’s by Ernst von Romberg. Pulmonary hypertension involves the constriction of the blood vessels in the lungs, or those that connect the organ to the rest of the body. The constriction prevents the patient’s heart from pumping blood efficiently through the lungs. This condition progresses over time and makes the pulmonary capillaries, veins, or arteries thicker and stiffer. The fibrosis of these pulmonary blood vessels results in an increased blood pressure within the organ and eventually impairing the flow of blood.

When the blood pressure within the lungs increases, the patient’s heart suffers greatly. The right ventricle can exhibit hypertrophy, making it more difficult for the heart to perform its task. Hypertrophy can then result in a condition called cor pulmonale or the failure of the right ventricle of the heart, which is designed to handle “low pressure” tasks, while the left ventricle deals with pumping more blood to places that require a higher amount of pressure. The right ventricle cannot deal with pumping more and more blood into the lungs and will fail to secure oxygen for itself in the long run.

There are also kinds of pulmonary hypertension that stems from a dysfunction in the left side of the heart. When the left ventricle of the heart is unable to perform its task, blood can pool inside the lungs and reverse the pressure back in the patient’s pulmonary system.

Pulmonary hypertension can also result in low levels of blood-carried oxygen in the lungs. When vital organs such as the lungs fail to receive enough blood, they will be damaged and unable to perform their tasks properly over time. When left unchecked, pulmonary hypertension in the third category will spread all over the patient’s pulmonary system.

Recurring blood clots can also cause pulmonary hypertension, which can result in the patient’s systems producing and releasing biochemical substances that make the blood vessels tighter.

Cause of Condition

The causes of pulmonary hypertension vary widely. Many experts subscribe to the classification system finalized at Dana Point, where the 2008 World Symposium on Pulmonary Arterial Hypertension was held. In the first category of the classification system, “pulmonary arterial hypertension or PAH,” causes can be idiopathic, hereditary, or associated with exposure to or consumption of certain drugs and toxins. PAH can also be a condition that coexists with HIV infection, connective tissue disease, congenital heart diseases, schistosomiasis, portal hypertension, or sickle cell disease and other types of chronic haemolytic anaemia.

The second category of PH, or “pulmonary hypertension owing to left heart disease,” can be caused by the dysfunction of the patient’s systolic or diastolic functions, as well as heart disease.

In the third category “pulmonary hypertension owing to lung disease and/or hypoxia,” PH can be a condition caused by interstitial lung disease, chronic obstructive pulmonary disease, chronic exposure to high altitudes, breathing difficulties caused by sleeping disorders, abnormalities in the patient’s physiological development, or alveolar hypoventilation disorders.

The fifth category “pulmonary hypertension with unclear multifactorial mechanisms” can be associated with the removal of the patient’s spleen, vasculitis or other forms of systemic diseases, glycogen storage disease, chronic kidney failure while undergoing dialysis, fibrosing mediastinitis, or the presence of tumours that obstruct the pulmonary capillaries, veins, or arteries.

Key Symptoms

It is important to note that the symptoms of pulmonary hypertension might not be easily noticeable over months or even years. It is for this reason that patients generally delay seeing a doctor in the early stages of the condition. However, the disease progresses over time, with the symptoms worsening in its wake.

Common symptoms of this condition include dyspnoea or shortness of breath, which is usually observed when the patient is performing strenuous activities. Over time, dyspnoea worsens and the patient can observe shortness of breath even while at rest.

Because the lungs are not properly oxygenated, patients also experience fatigue, dizziness, and fainting spells. The heart’s extra efforts to pump blood into the lungs can result in an uncomfortable pressure in the chest. As the disease progresses, the uncomfortable pressure can result in chest pains.

Patients suffering from pulmonary hypertension can also observe oedema or swelling of the legs and ankles. As the condition progresses, the patient can experience ascites, or swelling of the abdomen. Patients can also suffer from cyanosis, which is having a bluish tinge on the skin and lips, caused by the improper circulation of blood in the pulmonary system.

Heart palpitations, decreased appetite, abdominal pain, and racing pulse can also be telltale signs of pulmonary hypertension.

Who to See and Types of Treatment Available

Treatment for pulmonary hypertension varies according to their classification in the Dana Point system.

Medication is the most common type of treatment for PAH, with prostanoids, phosphodiesterase-5 inhibitors, and calcium channel blockers being common prescriptions.

Surgery can also be an option for patients. Atrial septostomy involves inserting a thin catheter into the septum to introduce a small balloon to open up the atria and increase the blood flow. Lung transplants can also be an option, especially if the patient is suffering from a serious lung disease that causes pulmonary hypertension.

References:

  • Channick RN, Rubin LJ. Pulmonary hypertension. In: Mason RJ, Broaddus VC, Martin TR, et al., eds. Murray and Nadel's Textbook of Respiratory Medicine. 5th ed. Philadelphia, PA: Elsevier Saunders; 2010:chap 52.

  • McLaughlin VV, Archer SL, Badesch DB, et al: American College of Cardiology Foundation Task Force on Expert Consensus Documents; American Heart Association; American College of Chest Physicians; American Thoracic Society, Inc; Pulmonary Hypertension Association. ACCF/AHA 2009 expert consensus document on pulmonary hypertension: a report of the American College of Cardiology Foundation Task Force on Expert Consensus Documents and the American Heart Association developed in collaboration with the American College of Chest Physicians: American Thoracic Society, Inc; and the Pulmonary Hypertension Association. J Am Coll Cardiol. 2009;53:1573-1619.

  • Rich S. Pulmonary hypertension. In: Bonow ROL, Mann DL, Zipes DP, Libby P, eds. Braunwald's Heart Disease: A Textbook of Cardiovascular Medicine. 9th ed. Philadelphia, PA: Elsevier Saunders; 2011:chap 78.

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